A dispensing valve for breathing gas is known from DE 28 27 131 C2. The regulating member for dispensing the gas is formed by a ball valve with a gas passage opening, and a ball is pressed by the admission pressure against the gas passage opening. The ball can be pushed out of the gas passage opening with a pin, which can be displaced in the longitudinal direction. The pin is actuated by a magnetic drive. The gas flow through the gas passage opening results from the path by which the ball is displaced in relation to the gas passage opening and the pressure difference between the two sides of the gas passage opening.
The area of the dispensing valve in which the admission pressure acts must always be designed for the maximum possible pressure in the case of the first error. This requires increased technical effort and special permits may possibly be necessary for certain gases.
Admission pressure compensation is frequently employed to make it possible to actuate dispensing valves with weak opening forces at high admission pressures. A dispensing valve with admission pressure compensation is described, for example, in DE 40 12 485 C1. A compensating piston with a pot-shaped diaphragm, which diaphragm is accommodated in a valve housing, is provided for admission pressure compensation. The admission pressure compensation takes place in such a way that a compensating force, which is generated at the pot-shaped diaphragm and the compensating piston, counteracts the force acting on the valve body. A safety means for liming the admission pressure is not provided. Such a safety means could be embodied with a separate pressure relief valve only.